Big ASS Fans a new trend in Warehouses and Auditoriums that requires careful code conciderations

Big Ass fans as they are commonly known and one company actually sells them under that name  are a popular way to move large amounts of air to help keep large spaces cool in summer and warm in winter . think of a paddle fan but these units have 6 foot blades on them and operate on 230 to 480 volt Three Phase power .Like the unit in Picture below.

 One of the problems with these big fans is because of the amount of air they move they need to be shut down during a Fire Event so most have a built in jumper you remove and connect in a relay from fire system to shut it down and lock it out when fire alarm activates.As you can see in picture below the red fire wire connected to the Power Flex " Variable Frequency Drive " which I recently wired in at a warehouse .

Because of the extreme force these fans produce careful consideration must also be made to insure personnel do not get close enough to be struck by the blades even though they do not move real fast they do have a lot of power behind them and I do not know if they have a break away clutch feature.
But you can bet as effective as they are the word is spreading and you will be seeing more of them in the future .